Cognitive Network

ABSTRACT

A reservation request is received for a data transport session. The reservation request contains a requested class of communication service through the asynchronous network. The state of the network along the route is then preferably determined and at least one end-to-end route through the network is obtained. The route is based on the requested class of communication service and the state of the network. The data transport session is then controlled, such that data is forced to travel along at least one route through the asynchronous network. This is preferably done by controlling multiple data controllers dispersed along the at least one route by mapping specific data protocols to specific routes, or mapping specific data protocols to specific ports in each data controller. If a state of the asynchronous network indicates that the route cannot transport data in conformity to the class of communication service, then the route is changed to a backup route through the network.

This application claims priority to U.S. patent application Ser. No.10/756,707, filed Jan. 12, 2004, which claims priority to U.S.Provisional Patent Application No. 60/439,573, filed on Jan. 11, 2003,the disclosure of which is incorporated fully herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to networking. In particular, the presentinvention relates to an end-to-end network control system for improvingQuality of Service (QoS), enhancing network and data security,availability, and reliability, monetizing network traffic, and reducingnetworking costs.

2. Description of Related Art

Data networks are generally said to be connection-oriented orconnectionless. Connection-oriented networks require an establishment ofa data transmission session between two nodes before transmission canbegin. Once communications are completed, the session is ended or torndown. Circuit-switched networks are connection-oriented because theyrequire a dedicated channel for the duration of the session. The mostubiquitous circuit-switched network is the Public Switched TelephoneNetwork (PSTN).

A connectionless network is a communications architecture that does notrequire the establishment of a session between two nodes beforetransmission can begin. The transmission of packets within InternetProtocol (IP) networks, for example, is connectionless. In general, IPnetworks include a collection of IP router peers, each of which is partof an Autonomous System (AS), where each router has a limited view ofthe network in real-time, restricted to the next “hop,” or connection,to an adjacent router. For example, in this environment, identicalpackets transmitted across the Internet may take completely differentroutes between the same source and destination. If a packet does notreach its destination, it is simply resent or discarded.

This characteristic inhibits carriers from guaranteeing Quality ofService (QoS) when transporting voice or other streaming or real-timedata services over connectionless networks, such as IP networks ingeneral and the Internet in particular. Because this “flaw” inconnectionless networks is inherent, streaming or real-time data traffichas historically been provided by connection-oriented communicationsarchitectures, like circuit-switched telecommunications networks.Connectionless networking works well for non-real-time transmissions,such as requests for Web-pages, email, or the like, but does not workwell for real-time or streaming transmissions such as voice orvideo-conferencing. In summary, the performance of connectionlessnetworks is inherently unpredictable.

Connectionless networks also have other drawbacks. For example, IProuters typically make sub-optimal routing decisions based on singleparameters, such as availability, without taking into accountappropriate combinations of other factors such as transport cost,network congestion, latency, required security, or other parameters.Managing data packets in this manner is inefficient and needlesslyexpensive, as management and control functions are replicated at eachrouter, and carriers must over-provision their networks (a waste ofresources) in order to even approach on-time delivery required bystreaming traffic.

In addition, connectionless data networks typically utilize in-bandsignaling and control, i.e., a single logical plane both to transportdata packets and to control communications among the various elements inthe network, such as routers or switches. As such, control informationis as accessible by users as the transmitted data, so both arevulnerable to a variety of attacks.

Still further, current IP transport technologies offered to networkcarriers, including Multi-Protocol Label Switching (MPLS), generally donot generate transaction records, making usage-based or premium servicebilling all but impossible. The industry's answer has beensubscription-based billing or flat pricing, an inefficient andunprofitable economic model for streaming or real-time data traffic thathas led to cost cutting with an inevitable and consequential erosion inservice levels.

In response to the above concerns, the Communications industry hasinvested billions of dollars in an attempt to provide predictablenetwork performance. Attempted solutions include MPLS, RouteOptimization, and Deep-packet Discovery. None of these technologies,however, have succeeded in addressing the above mentioned concerns. Eachof these “solutions” has one or more of the following inherentarchitectural flaws: a connectionless network cannot guaranteepredictable performance or accurately track usage details; in-bandcontrol limits security by exposing commands to users; stateless networkcontrol cannot provide timely network response to changing conditions;and distributed, autonomous control logic cannot extend network controlfrom end-to-end or coordinate usage for optimal efficiency.

Accordingly, a method and system for providing predictable and reliablenetwork performance in an IP network, while addressing the abovementioned drawbacks and concerns, would be highly desirable.

BRIEF SUMMARY OF THE INVENTION

According to one embodiment, there is provided a system/method forcontrolling on-demand sessions in asynchronous networks, enablingenhanced security, and deterministic performance, while enhancing thesecurity and predictability of existing best-effort connectionlesstraffic, and monetizing data transport services (increasing revenues)with reduced operating costs for carriers in IP-based and other datatransport networks.

According to the invention there is provided a computer-implementedmethod for end-to-end control of data transported through anasynchronous network. A reservation request is received for a datatransport session, such as from at least one serviced device or isgenerated within a management plane. The reservation request contains arequested class of communication service through the asynchronousnetwork. The state of the network along the route is then preferablydetermined by instructing a measurement signal to be transported alongat least part of the route and determining whether the measurementsignal was transported and received in accordance with predeterminedperformance characteristic limits. Determining the state of the networkpreferably utilizes a common timing reference with sufficient accuracyto enable one-way delay measurements between data controllers dispersedthroughout the network. Furthermore, a time interval of such determiningis preferably dynamically adjusted based on current characteristics ofthe route between the data controllers. In another embodiment,determining the state of the network comprises determining parametricguard band limits; ascertaining a state of at least part of the network;determining whether the state is outside of the guard band limits; andtransmitting an alarm, if the state is outside of the guard band limits.The state of the network is then transmitted to a management controllervia a out-of-plane dedicated physical circuit or an in-plane dedicatedvirtual circuit.

At least one end-to-end route through the network is then obtained,preferably from an inventory of multiple predetermined routes. The routeis based on the requested class of communication service and the stateof the network. The data transport session is then controlled, such thatdata is forced to travel along at least one route through theasynchronous network. This is preferably done by controlling multipledata controllers dispersed along the at least one route. Also in apreferred embodiment, the controlling comprises mapping specific dataprotocols to specific routes, or mapping specific data protocols tospecific ports in each data controller. If a state of the asynchronousnetwork indicates that the route cannot transport data in conformity tothe class of communication service, then the route is changed to abackup route through the network.

Also in a preferred embodiment, the class of service is dependent onsome weighted combination of the required bandwidth, transport datarate, maximum delay allowed by the class of communication service,variations in delay allowed by the class of communication service,maximum allowed transport cost, allowed priority relative to other databeing transported, or required reliability of the class of communicationservice.

Usage patterns of the data transport session may be monitored orrecorded, preferably in real-time. Also, the actual and planned use of aroute may be recorded to enable differentiated usage-based billing. Thesystem preferably collects data regarding the current configuration of aconnectionless network to establish the configuration of a datacontroller so that the data controller can support connectionlesstraffic.

According to the invention there is also provided a system forend-to-end control of data transport through a connectionless network.The system includes an asynchronous network, multiple data controllersdispersed throughout the asynchronous network, and at least onemanagement controller coupled to the multiple data controllers via acircuit. The at least one management controller preferably containsinstructions for: receiving a reservation request for a data transportsession, where the reservation request contains a requested class ofcommunication service through an asynchronous network; obtaining atleast one end-to-end route through the network, where the route is basedon the requested class of service and a state of the network; andcontrolling the multiple data controllers, such that data is forced totravel along the at least one route. In a preferred embodiment, thenetwork is an Internet Protocol (IP) network. Each data controllerpreferably includes a mechanism configured to change a destinationaddress of each data packet in the data transfer session to direct thedata packet to a next data controller along the route. In a preferredembodiment, such a mechanism is an in-bound Content Addressable Memory(CAM) and an out-bound CAM.

Accordingly, the present invention is a cognitive system that providesthe necessary control for sessions with enhanced security anddeterministic performance. The cognitive network is stateful, i.e., isaware of the status of each part of the managed network within arequisite timeframe to enable near-real-time control of the overallnetwork. A moving target, with today's technology thisnear-real-timeframe ranges from hundreds of microseconds through seconds(10⁻⁴-10⁰ seconds), depending on what aspect of the network is beingobserved or controlled. The cognitive network also hasconnection-oriented network behavior using logically coherent managementand out-of-band signaling. The cognitive network is also preferablylinearly scalable, fault-tolerant, backward-compatible with any packet,cell, or frame data transport infrastructure, and incrementallydeployable.

The cognitive network's architecture comprises in-bearer-planemeasurement and control devices, referred to herein as data controllers,interconnected via an out-of-band, end-to-end management and controlsystem preferably using dedicated control circuits. This managementcontroller preferably acts in near-real-time based on network statedata, allowing the network to constantly adapt to changing conditions.This network also preferably features active link monitoring atsub-millisecond intervals, industry-standard connection setup, and rapidfault recovery (preferably within SONET Automatic Protection Switchingtimes). Furthermore, the cognitive network provides pro-active controlfor on-demand switched virtual circuits, guaranteed end-to-end QoS,requirements-based routing, and unparalleled security and privacy. Thecognitive functions of the network also allow for activity monitoring,detection, analysis, and mitigation of, and active defensivecountermeasures against, malicious network attacks. The cognitivenetwork can assume the characteristics of both connectionless andconnection-oriented networks.

Routing logic is moved out of the switching devices and into anout-of-band management plane assisted by an off-line route generator,residing in a cognitive plane. With near real-time visibility into thestate of the network, the preferred automated management function makesoptimal end-to-end routing decisions that normally occur only once perflow from end-to-end rather than per packet and per hop. These decisionsare sent simultaneously to the affected switching devices used in theprimary route and back-up route(s). These features reduce the overallnetwork computational load by several orders of magnitude, yielding acorresponding increase in efficiency and reduction in capital andoperating expenditures.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the nature and objects of the invention,reference should be made to the following detailed description, taken inconjunction with the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a cognitive network architecture,according to an embodiment of the invention;

FIGS. 2A and 2B are block diagrams of one of the data controllers shownin FIG. 1, differentiated by performance levels;

FIG. 3 is a block diagram of one of the management plane controllersshown in FIG. 1;

FIG. 4 is a block diagram of one of the cognitive plane controllersshown in FIG. 1;

FIGS. 5A and 5B are block diagrams of the header address conversion(HAC™) printed circuit card shown in FIG. 2, differentiated byperformance levels;

FIG. 6 is a block diagram of the Content Addressable Memory (CAM) tablesshown in FIG. 5; and

FIGS. 7A through 7D are flow charts for a method for routing data acrossa network, according to an embodiment of the invention.

Like reference numerals refer to corresponding parts throughout theseveral views of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is schematic of a cognitive network 100, according to anembodiment of the invention. The cognitive network 100 is made up ofthree distinct functional layers or planes, namely a cognitive plane102, a management plane 104, and an bearer plane 106. The bearer plane106 is similar in many respects to current IP networks, such as theInternet. For example, customer premises equipment (CPE) 108 communicatewith their respective Service Provider's Aggregation Point (SPAP) 110via any suitable communication link, such as T1, Digital Subscriber Line(DSL), or cable connection. The CPE may include a DSL modem, cablemodem, or Voice Over IP (VoIP) telephone, or the like. The SPAP includesor provides connectivity to at least the same components as the datacontrollers described below. Also, although not shown, existing IPnetwork elements, such as IP routers and switches, are dispersedthroughout the network, as is well understood by those skilled in theart. For example, each IP data link 114 may be a dedicated direct linkor may include multiple routers and/or switches coupled to one another.

What distinguishes the bearer plane over current IP networks is that:(1) data controllers 112 (described in further detail below) arestrategically dispersed throughout the network between existing datalinks 114 to direct data traffic over the bearer plane 106, and (2) theaggregation point 110 and the data controllers 112 communicate directlywith the management plane 104 and/or the cognitive plane 102 overout-of-bearer-plane circuits.

In use, a first user using customer premises equipment 1 (CPE 1) maycommunicate with a second user using customer premises equipment 2 (CPE2) over bearer plane 106 through aggregation points 1 and 2 (SPAP 1 andSPAP 2) 110, one or more data controllers 112, and one or more IP datalinks 114 (that may themselves include one or more IP routers, switches,or the like).

The management plane 104 preferably includes multiple managementcontrollers 116 (described in more detail below). Each managementcontroller 116 preferably communicates directly with multiple datacontrollers 112 via out-of-bearer-plane communication links 122. Thecommunication links 122 are preferably distinct physical out-of-planecircuits. Alternatively, the communication links 122 may be distinctvirtual circuits established within the bearer plane 106. The managementcontrollers 116 also preferably communicate with one another viaout-of-bearer-plane communication links 124. The out-of-bearer-planecommunication links 122 preferably have known and stable operating andperformance characteristics. The management controllers 116 preferablyutilize these known performance characteristics to transmit a timingreference to each data controller 112 in bearer plane 106 with requisiteaccuracy to successfully measure network transport events. Transportingtypical voice traffic, for example, requires meeting severalindustry-standard network performance criteria: a bandwidth of 64k-bits/sec, a maximum delay (latency) through the network from end toend of, for example, 200 msec, a specified jitter (instantaneousvariations in latency from packet to packet) limit, etc. In order tomeasure latency and jitter to the requisite degree of precision for thisservice, the overall cognitive network must be able to detect and manageevents of a duration of the order of tens of milliseconds. In general,controlling a process requires measuring that process. The measurementprocess in this service case preferably probes network links at aninterval sufficiently small to manage these ˜10 msec events (say everyfew hundred microseconds). To perform this measurement with therequisite accuracy, the timing reference needs to be synchronized ineach data controller 116 to within ±10 microseconds (μsec). There areseveral well known means for providing a timing reference with thisrequisite precision.

The cognitive plane 102 includes one or more cognitive controllers 118.Each cognitive controller 118 is preferably coupled to one or more ofthe management controllers 116 via out-of-bearer-plane communicationlinks 120. The cognitive controllers 118 also preferably communicatewith one another via dedicated circuit communication links 126. Thededicated communication links preferably have known and stable operatingand performance characteristics. The cognitive controllers 118, amongother functions, preferably compute routes for requested classes ofservices. Such computation of routes preferably does not need to beperformed in real-time.

Furthermore, the management and cognitive controllers preferablyincludes a requisite degree of fault tolerance and redundancy.Therefore, failure of one or more of these controllers does not have acritical effect on the system.

FIGS. 2A and 2B are block diagrams of one of the data controllers 112shown in FIG. 1. The block diagrams of data controller 112 depicted inFIGS. 2A and 2B differ in architecture slightly to accommodate aspectrum of performance (bandwidth) requirements expected in normalnetwork use. In FIG. 2A, the data controller 112 shares a switchingelement called the HAC™ card 214 (see FIGS. 5A and 5B) among the variousbearer plane interface ports for relatively low bandwidth applications.In FIG. 2B, the data controller 112 contains a separate HAC™ card 214for each bearer plane port interface for relatively higher bandwidthapplications.

The data controller 112 preferably includes: at least one data processoror central processing unit (CPU) 204; memory 218; communicationcircuitry 210 for communicating with the management plane controllers116 (FIG. 1) and/or other data controllers 112; a power source 202configured to be coupled to a source of power; at least one HeaderAddress Conversion (HAC™) card 214 for converting the headers of datapackets as described below; port interfaces 216 and 236; and at leastone bus 212 that interconnects these components. The data controller 112may also optionally include one or more user interface devices, such asa monitor 208, and a keyboard/mouse 206. Furthermore, one or more of theport interfaces 236 are preferably coupled to one or more HAC™ cards214. These port interfaces 236 are preferably Network Interface Cards(NICs). Each port interface 236 preferably communicates over the bearerplane 106 using one or more communication protocols, such as ATM,Ethernet, or the like. In addition, port interface(s) 216 communicatedirectly with the management plane 104 (FIG. 1) via at least one means,such as, for example, a dedicated circuit using any suitablecommunication protocol, such as asynchronous transfer mode (ATM), ATMAdaptation Layer 1 (AAL1), or the like.

The memory 218 preferably includes high-speed random access memory andmay include non-volatile memory, such as one or more magnetic diskstorage devices. The memory 218 preferably stores an operating system220, such as LINUX®, UNIX® or WINDOWS®, that includes procedures forhandling basic system services and for performing hardware-dependenttasks. The memory 218 also preferably stores communication procedures222 used for communicating with the management plane controllers 116(FIG. 1), other data controllers 112, and the remainder of the existingnetwork. In particular, the communication procedures 222 are used forreceiving routes and/or session identifiers (IDs) from the managementcontrollers; reporting state information to the management controllers;receiving data frames or packets; and for transmitting data frames orpackets, as described below in relation to FIGS. 7A-7D.

The memory 218 also preferably includes: state determination procedures224; filter procedures 226; link characteristics 228; alarm procedures230; physical and network security procedures 232; installationprocedures 234; and a cache for temporarily storing data. The statedetermination procedures 224 determine the state of the networksurrounding and including the data controller 112. Such a determinationof the state preferably happens in near-real-time (i.e., the networkstate is sufficiently current so as to be useful in controlling thenetwork's behavior) with variances outside predetermined linkperformance limits forwarded to the management controllers. In apreferred embodiment, the state determination procedures 224 include“heartbeat” packet generation and processing procedures that issueheartbeat packet(s) every few hundred microseconds (or some othersuitable interval determined by network characteristics) and report onthe transmittal and receipt of the heartbeat packet(s). The heartbeatpackets are preferably of varying lengths and have varying payloads, butcontain at the least an accurate timestamp that is synchronized with thetime reference of the receiving data controller. The heartbeat intervalis preferably varied as needed to trade off overhead versus testinggranularity. The accumulated data allows the management plane to computea stateful view of the relevant portion of the network from end to end.In other words, the heartbeat generation and processing proceduresrequest each of the data controllers to generate and transmit aheartbeat packet to and through a neighboring data controller. The datacontroller then reports back to the management controller if it did notreceive the heartbeat packet in a manner consistent with thepredetermined limits. In this way, the data controllers can continuallyreport their operating state and/or the operating state of thesurrounding network links to the management controllers.

The filter procedures 226 assess link state changes for relevancy andare mirrored with related procedures in the management controller. Datarelating to the link characteristics 228 are stored in the datacontroller 112 and reported to the management plane 104 from time totime. The alarm procedures 230 are used to generate and transmit analarm to the management controllers when a data link or the datacontroller 112 itself is not operating according to a minimum predefinedstandard. Further details of the operation of the data controllers aredescribed below in relation to FIGS. 7A-7D.

Furthermore, each data controller preferably contains a range (guardband) around each state parameter measured or monitored. Directlymeasured parameters include latency, availability, packet loss, and biterrors, where each such parameter is measured for a variety of packetsizes and insertion rates. The system accumulates these data and addsother calculated and entered parameters, including, but not limited to,reliability, link cost, geographic location, carrier security level,jitter, bit error rates, bandwidth, packet loss rates, and any otheruseful parameter that can be specified, measured, inferred, orcalculated. Taken together, these parameters form the basis forconstructing data communication sessions with defined “Heuristics ofService” (HoS), a superset of Quality of Service (QoS). In operation,applications may request a given mix of parameters or HOS™ class, andthe system provisions virtual circuits to satisfy the needs of therequested service.

FIG. 3 is a block diagram of one of the management plane controllers 116shown in FIG. 1. The management plane controller 116 preferablyincludes: at least one data processor or central processing unit (CPU)302; memory 316; a communication interface 304 for communicating withthe data controllers 112 (FIG. 1), other management plane controllers116, and/or cognitive plane controllers 118 (FIG. 1); a power source 308configured to be coupled to a source of power; and at least one bus 310that interconnects these components. The management plane controllers116 may also optionally include one or more user interface devices, suchas a monitor 312, and a keyboard/mouse 314.

The memory 316 preferably includes high-speed random access memory andmay include non-volatile memory, such as one or more magnetic diskstorage devices. The memory 316 preferably stores an operating system318, such as LINUX®, UNIX® or WINDOWS®, that includes procedures forhandling basic system services and for performing hardware dependenttasks. The memory 316 also preferably stores communication procedures320 used for communicating with the data controllers 112 (FIG. 1), othermanagement plane controllers 116, and/or cognitive plane controllers 118(FIG. 1). In particular, the communication procedures 320 are used forreceiving state reports from the data controllers; receiving routes fromthe cognitive plane controllers; and/or communicating routes and/orsession IDs to the data controllers, as described below in relation toFIGS. 7A-7D.

The memory 316 also preferably includes: filter procedures 322 forfiltering relevant state information from non-relevant information;failure procedures 324 for determining whether failure or relevant statechange have occurred of a data controller or other part of the network;a state database for storing state information on the status of thenetwork; route select procedures 327 for selecting routes that qualifyfor the class of service requested; and a cache 328 for temporarilystoring data. It should be appreciated that the state database 326 maybe stored locally, externally, or elsewhere. Further details of theoperation of the management plane controllers are described below inrelation to FIGS. 7A-7D.

FIG. 4 is a block diagram of one of the cognitive plane controllers 118shown in FIG. 1. The cognitive plane controller 118 preferably includes:at least one data processor or central processing unit (CPU) 402; memory416; a communication interface 404 for communicating with the managementplane controllers 116 (FIG. 1) and/or the other cognitive planecontrollers 118; a power source 408 configured to be coupled to a sourceof power; and at least one bus 410 that interconnects these components.Each cognitive plane controller 118 may also optionally include one ormore user interface devices, such as a monitor 412, and a keyboard/mouse414.

The memory 416 preferably includes high-speed random access memory andmay include non-volatile memory, such as one or more magnetic diskstorage devices. The memory 416 preferably stores an operating system418, such as LINUX®, UNIX® or WINDOWS®, that includes procedures forhandling basic system services and for performing hardware dependenttasks. The memory 416 also preferably stores communication procedures420 used for communicating with the management plane controllers 116(FIG. 1) and/or the other cognitive plane controllers 118. Inparticular, the communication procedures 420 are used for transmittingroutes to the management plane controllers, as described below inrelation to FIGS. 7A-7D.

The memory 416 also preferably includes: a route menu 422 of all primaryand backup routes for particular classes of service; route generationprocedures 424 for computing the primary and backup routes; and a cachefor temporarily storing data. Further details of the operation of themanagement plane controllers are described below in relation to FIGS.7A-7D.

FIGS. 5A and 5B are block diagrams of the header address conversion(HAC™) card 214 shown in FIGS. 2A and 2B. For lower performance(bandwidth) data controllers, the HAC™ card 214 shown in FIG. 5A isshared among the port interfaces 236. For higher performance (bandwidth)data controllers, a separate HAC™ card 214, shown in FIG. 5B, is usedfor each port interface 236.

The HAC™ card 214 is preferably coupled to the PCI bus 212 (FIGS. 2A and2B) via a PCI bus slave 508. In the lower performance embodiment shownin FIG. 5A, the HAC™ card 214 is preferably coupled to one or more portinterfaces 236 via an Intra-DC (IDC) bus master 516 and IDC bus 522. Inthe higher performance embodiment shown in FIG. 5B, the port interface236 comprises a media-specific adapter 524 (An MSA allows the device tobe readily adapted to any number of different types of transport media.)for coupling port interface 236 to IP links 114 (FIGS. 1 and 2), a usernetwork interface processor chip 526 for processing layer 2 packetheaders, and a serializer/deserializer (SERDES) 528 for coupling to theIDC bus 522. Components 524, 526, and 528 are commonly used to connectsystems to high-speed optical networks. Equivalent components areavailable to connect systems to high-speed electronic networks.

The HAC™ card 214 also preferably includes control and pre-processinglogic 500; a clock reference 502 for keeping an accurate timingreference preferably within the range of tens of microseconds; a searchmeans, such as an in-bound Content Addressable Memory (CAM) array 504,and associated bus interface register 510; an out-bound CAM 518associated bus interface register 512; and a packet buffer 520. Thecontrol and pre-processing logic 500 is coupled to and controls thecomponents within the HAC™ card 214.

The HAC™ card 214 also separates the bearer plane 106 from themanagement plane 104, thereby reducing opportunities for maliciousattack and unauthorized control of the network. The bearer plane 106traffic exists only on the bearer plane 106 so that no network user canaccess the management plane 104 or the cognitive plane 102. To that end,management plane 104 traffic enters the HAC™ card 214 via bus 506, andbearer plane 106 traffic enters HAC™ card 214 via separate bus 514.

The CAM arrays 504 and 518, also known as “associative storage,” arespecialized memory chips in which each bit position can be comparedagainst a corresponding bit position in an input called a Comparand. Inother words, the CAM's content is compared in each bit cellsimultaneously to the corresponding bit cell in the Comparand, allowingfor very fast table lookups. Since the entire chip is compared at thesame time, the data content can often be randomly stored without regardto an addressing scheme which would otherwise be required. However,since CAM chips are considerably smaller in storage capacity thanregular memory chips, additional CAM chips must be added (cascade mode)as the network expands. The addition of CAM chips allows for linearscalability as the network traffic grows, thereby serving a largernumber of users without requiring large upfront costs, without breakingdown, and without requiring major changes in procedure.

In use, data packets received at the port interface(s) 236 have relevantportions of their headers sent through header pre-processing logiccontained in control logic 500 to in-bound CAM Array 504. The packetenters the packet buffer 520 (FIGS. 5A and 5B), which is preferablySynchronous Dynamic RAM (SDRAM), while the header is being processed bythe CAMs. Relevant portions of the header enter the in-bound CAM Array504 and are compared against an in-bound lookup table 602 (FIG. 6)stored in CAM 504.

The header portions participating in the comparison depend on the typeof flow being managed. For example, if the flow to be managed is using atag to aggregate traffic, the Session ID and other Protocol Data Unit(PDU) and Session Data Unit (SDU) information may be used to switchtraffic to the proper Physical (Phy) Port, as shown in header portion604 in FIG. 6. The remainder of the header portions (Source Address(SA), Destination Address (DA), and Physical or Logical (Phy/Logical)Port Address) are considered “don't care” (forced match) for thecomparison. If, on the other hand, individual flows are being managed,header portion 606 would be compared where the Session ID is “don'tcare.” Additionally, if a Virtual Private Network (VPN) tunnel is beingmanaged, the relevant header portion 608 would be compared where theSession ID and Phy/Logical Port Address are “don't care.” Further, ifthe managed flow comprised aggregated best effort (BE) traffic, headerportion 610 would be compared where only some of the DA (a DA range)would participate, and the remainder of the relevant header portionwould be “don't care.”

If the session ID, source address, destination address or other SDU andPDU data are not located in the lookup table 602 (FIG. 6) (so-called“non-registered traffic”), then the packet header remains unchanged, andthe packet is routed to any one of several possible processes, includingbut not limited to (FIG. 7D), forward packet process 815, analyze packetprocess 816, or discard packet process 814, in which case no operationoccurs on the packet, as if the packet had not passed through the datacontroller 214 at all. Alternatively, the data controllers may blocknon-registered traffic, passing only managed session trafficspecifically addressed to the data controller. Also, alternatively, thedata controllers may divert traffic to special handling processes, suchas where the traffic is malicious attack traffic, and the specialhandling processes might include attack mitigation or counter-measureprocesses. Because the data controllers do not process other signals orother bearer plane control signaling, the data controllers are lessvulnerable to traditional Denial of Service (DoS) attacks.

If, however, the appropriate combination of session ID, source address,and destination address is located in the in-bound lookup table 602(so-called “registered traffic”), then the in-bound CAM 504 sends aMatch Address to out-bound CAM 518, which locates a header entrycorresponding to the located header portion from in-bound CAM 504 in anout-bound CAM 518 lookup table 604. A selected header portion(s) 612,for example, located in the out-bound lookup table 604 is(are) thensubstituted for the corresponding portion(s) of the packet headerlocated in the in-bound lookup table 602, and the packet is transmittedtowards its new destination via one of the port interfaces 236. In thisway, the packet is forced to travel to a controlled destination, i.e.,toward the next data controller along the predetermined route generatedand controlled by the cognitive controllers and the managementcontrollers, respectively. This ability to switch registered trafficover characterized IP links in a deterministic way enables the cognitivenetwork to assure QoS across the entire network, including over multiplecarriers' networks.

FIG. 7A is a flow chart of a method 700 for cognitively determining thestate of the network and for generating routes through the network. Eachdata controller 112 (FIG. 1) in the network periodically receivesallowed states of the surrounding network at step 702 (guard bandlimits). In other words, the state determination procedures 224 (FIGS.2A and 2B) in each data controller, either on their own or based oninstructions received from the management controllers 116, periodicallydetermine in step 704 the current or last-known status, or condition, ofa process, transaction, or setting, such as transmittal and/or receiptof a heartbeat packet. The state determination interval varies as neededto reflect a sufficiently current condition to allow cognitive routeplanning with predictable, deterministic delays through the network.Said intervals can vary, but need to reflect the state of links with aresolution smaller than the error tolerance of the data transport beingmanaged, for example, a millisecond might be preferred in order tocontrol events on a scale of tens of milliseconds, depending on manyfactors, including, for example, link performance stability.

If this state information falls outside pre-determined and variableparametric guard band limits (determined in step 708), an alarm is thentransmitted to a management plane controller 116 at step 714. Themanagement plane controller 116 then receives the state information,including the alarm, at step 706, and the failure determinationprocedures 324 (FIG. 3) determine in step 720 whether the datacontroller or network has failed based on the received state informationat step 706. If analysis of the alarm in step 720 indicates a failurehas been reached when the received state information does not meet apredetermined minimum standard, a decision is made in step 720 as towhat preferably pre-planned responsive action is required. One possibleaction would be to send to relevant data controller(s) upstream from thefailing link or data controller a message to switch the routing ofsubsequent traffic to a back-up route (B in this example) at step 724.Other actions are possible, such as, for example, downgrading thesessions being transported over the subject link or data controller 112such that the traffic passing over that link or through that datacontroller is provided with a lower quality or class of transportservice. Using the out-of-band control and end-to-end knowledge of thestate of the overall network afforded by management plane 104 working inconcert with cognitive plane 102 and the measurements taken by datacontrollers 112 allows the optimization of network operation around anydefined set of constraints (cost, performance, reliability, security,priority, etc.).

This instruction to switch from the primary route to the appropriaterelevant backup route is received and stored by the data controllers inthe CAM arrays at step 726. In a preferred embodiment, the system canswitch a flow to the back-up routes within a short enough interval, say50 msec, of the onset of a problem, to avoid material interruption ofthe flow, preserving QoS to a required level.

Whether or not the received state information indicates responsiveaction, the state information is then evaluated for relevancy by thefilter procedures 322 (FIG. 3) at step 710. For example, informationabout unreasonable or anomalous state changes is filtered from theremainder of the state information, thereby reducing the size of andload on the state database that needs to be managed and the volume oftraffic that needs to be transported between management plane 104 andbearer plane 106. The relevant or filtered state information is thenposted to, or stored in, the state database 326 (FIG. 3) at step 712.

As the data controllers periodically report their state and the state ofthe network data transport links, the state or volume of the observedunmanaged data sessions, and the state or volume of the managed datasessions, the state database 326 (FIG. 3) is continually updated withthe latest network state information. As new data controllers are placedinto service, they will automatically begin reporting their state andupdating the state database with new state information for new parts ofthe network. Similarly, if data controllers are taken out of service orfail, the management controllers will stop receiving state informationfrom those data controllers and will update the state databaseaccordingly.

At any time, the cognitive controllers 118 access the state database 326(FIG. 3) to compute primary and backup routes for different types ofservice, at step 716. For example, the most reliable, highest performinglinks will be used as components to construct service routes with a highQoS, while the less reliable links will be used as components toconstruct service routes that have a lower QoS. The routes are thenstored for later use in the route menu 422 (FIG. 4) at step 718. It isnot necessary that the route computations occur in real time, as theroutes are computed ahead of time and in the background and stored forlater use. Routes are calculated in such a way as to optimize thenetwork through the use of a series of related formulae generallyreferred to as linear programming. In this way, use of network resourcescan be managed to optimize services, reducing undesirable effects suchas cost or overloading the best-performing data transport links andmaximizing desirable effects such as revenues or use of minimallyperforming data transport links. Failure responses are calculated inadvance in much the same manner by first altering the matrix of linkstate parameters and then optimally solving the network loading problem.In this way optimal responses to foreseeable changes in the state of thenetwork are pre-calculated and stored as part of the route menu for useas and when necessary.

FIGS. 7B-D are flow charts showing a method for routing data across anetwork, according to an embodiment of the invention. Initially, when auser of the service desires to send data across the network, the usercompletes a reservation request for a particular class of service atstep 732. The reservation request may be completed manually orautomatically, for example as when a user lifts the receiver oftelephone that uses a voice-over-IP (VoIP) service, a reservationrequest is formulated requiring a bi-directional, full duplex, voicequality, data transfer. In a preferred embodiment, standard reservationprotocols, such as SIP or H.323, are used to reserve the desiredservice.

The reservation request is transmitted by the user's Customer PremiseEquipment (CPE) toward a DC in the user's SPAP at step 734. Thereservation request is received by the SPAP at step 736, which thenrequests one or more routes for the particular reservation request fromthe management controller, at step 738. The reservation request can bereceived either explicitly, such as by a user requesting a particularclass of service, or implicitly, such as by the type of data transportbeing made, like a VoIP call being made. Alternatively, the reservationrequest may be generated internally by the data controller 110 (FIG. 1).The request for routes includes the class of service required, forexample, a voice-quality session at the requisite cost, reliability,security, priority, etc. The management controller receives the requestfor routes, at step 740, and obtains such routes at step 744.

As shown in FIG. 7C, to obtain routes, the route select procedures 327(FIG. 3) determine, at step 790, whether there are any routes in theroute menu 422 (FIG. 4) that qualify for the class of service requested.If there are no routes in the route menu that qualify for the class ofservice requested (790—No), then the management controller requests thecognitive controller to calculate the new routes, using the routegeneration procedures 424 (FIG. 4) at step 792. The new route(s) arethen posted to or stored in the route menu 422 (FIG. 4) at step 796.

If there are no qualified routes available (step 797), the managementcontroller signals the requesting user at step 798 indicating that theuser should try again later. Alternatively, at step 798, the managementcontroller could suggest alternatives or renegotiate the requirementsfor the session such that available routes are deemed qualified.

If there are routes in the route menu that qualify for the class ofservice requested (790—Yes), or once the new route(s) have been postedat step 796, a qualified primary route is selected from the route menuat step 794. One or more backup routes may also be selected at step 800,depending on the requested class of service.

Returning to FIG. 7B, once qualified route(s) are obtained at step 744,the required DC update information (CAM array updates) is transmitted tothe Data Controllers (DCs) that require the information. The DC updateinformation is received by the DC at step 776, which then transmits aninstruction to the CPE to initiate the data transmission session at step778, directing its registered traffic to DC0 in SPAP1.

At the same time as the management controller transmits the required DCupdate information to DC0 at SPAP1, at step 746, the managementcontroller preferably transmits the required DC update information (CAMarray updates) needed to process the data session packets along theselected route(s) to all data controllers 112 that require suchinformation along both the primary and backup route(s), if any. Suchspecific information, and any other control traffic between themanagement plane 104 and the bearer plane 106, is preferably encrypted.Each data controller along the route(s) then receives the required DCupdate information (look-up tables 602 and 604 stored in CAMs 504 and518), which may include, but is not limited to, session ID and/or sourceand destination packet addresses, and/or tag information, at steps 750and 762, and updates their CAM tables 602 and 604 (FIG. 6) at steps 752and 764 respectively such that the packets can be directed along thedesignated route(s) between DCs.

After the instruction is transmitted to the CPE to initiate the datatransmission session at step 778, the instruction is received by the CPEat step 780, which then transmits the packet(s) toward SPAP1 and DC0 atstep 782. The packet(s) are received by the DC at step 784, and, ifnecessary, the header of the packet(s) is changed by the HAC™ card 214in DC0, at step 786, to force the packet to be routed along the primaryroute determined by the system.

Further details of how the header is changed will be explained withreference to FIG. 7D. The packet is received by the data controller'sHAC™ card 214 (FIG. 2) at step 802. The packet is passed into the packetbuffer 520 (FIGS. 5A and 5B), while the header is examined. The in-boundCAM Array 504 (FIGS. 5A and 5B) is searched to identify the packet bymatching some combination of attributes, which might include the sessionID, source address, and/or destination address, and a tag, from thereceived packet's header at step 804. If a match is not located(806—No), then the control logic determines whether the packet should bediscarded, forwarded, or subject to alternative handling at step 812.Alternative handling may include any number of procedures including, butnot limited to, passing the packet along intact or analysis at step 816.Analysis might include, for example, determining if this packet ismalicious traffic and launching counter measures against the associatedattack. If the packet is to be discarded (812—Yes), then the packet isdiscarded at step 814.

If a match is located (806—yes), then the control logic modifiesrelevant portions of the header with required new header data from theout-bound CAM array 518 (FIG. 5), at step 808, and sends the revisedpacket to the destination port interface 236 (FIG. 5) at step 810. Forexample, the header is changed in DC0's HAC™ card to add a session ID,and to change the source IP address to DC0's source address, and thedestination address to that of the next data controller along the route(DC1 in this example). The revised packet is then transmitted to thedestination address contained in its revised header at step 788. Ingeneral, the destination address will be the next data controller alongthe predetermined route. Between data controllers, the packet will berouted via IP routers, direct connection, switches, or the like, as iswell understood in the art. Accordingly, the more data controllersprovided throughout the network, the more control the system has overthe routing and the better able the system is to deliver service with adefined QoS.

The packet is subsequently received by the second data controller (DC1)at step 754. The header is changed, if necessary, at step 758, and thepacket transmitted to the next data controller at step 760. Changing theheader at step 758 is identical to step 786 described above. The packetis then received by the third data controller (DC2) at step 766, theheader changed, if necessary, at step 770, and the packet transmitted tothe next data controller at step 772. Changing the header at step 770 isidentical to step 786 described above. At the final DC, near theoriginal destination address, the final DC destination address in theheader is changed to the original destination address, e.g., CPE2. Thepacket(s) are then received by the original destination (CPE2) at step774. Sessions can be unidirectional or bi-directional as required by theusers' applications.

Accordingly, the invention realizes several benefits, including:

1) Management that resides outside the IP bearer plane can orchestratethe routing of traffic in a highly efficient manner, because routingcomputations are performed with the benefit of more complete andstateful information about the network and the demands being placed onit in one logically cohesive fault-tolerant plane rather than similarcalculations being replicated at each router with incomplete and out ofdate information about the network and the demands being placed on it.

2) Pro-actively directed data traffic, using data transport linksqualified by the management plane based on state information collectedin the bearer plane, such that the traffic can traverse the IP bearerplane with deterministic and predictable performance. Unlike incurrently deployed connectionless data networks, said performance can beguaranteed by the data carrier, raising the value of data transportservices while lowering transport cost through increased efficiency andloading optimization.

3) Removing control information from the data transport bearer plane andplacing it on separate connections for use by the management planereduces the vulnerability of the data transport bearer plane to Denialof Service (DoS) attacks and other security breaches in a manner similarto security enhancements made in telephony networks of the past.

4) As packets for sessions under the control of the system areaggregated into larger flows because they are all assigned the samesource and destination addresses in the core, the aggregated flows arevery difficult to scan or “sniff” for private information.

5) The system preferably collects and retains session records in adatabase similar to the Call Detail Records (CDRs) that telephonecompanies are accustomed to recording and using. Such records arepreferably backward-compatible with the standard billing softwarealready used by carriers. This facet allows carriers to monetize the IPtraffic they carry based on the type of traffic, its duration, itsdistance, and its quality (value) for the first time, enabling new andprofitable billing models for IP transport.

6) This network architecture uses well known principles of balancinginventories of resources (routes or links through the network withrequisite characteristics) against users' demands in order tosignificantly raise network efficiency, lowering operating and capitalcosts.

The foregoing descriptions of specific embodiments of the presentinvention are presented for purposes of illustration and description.For example, any methods described herein are merely examples intendedto illustrate one way of performing the invention. They are not intendedto be exhaustive or to limit the invention to the precise formsdisclosed. Obviously many modifications and variations are possible inview of the above teachings. For example, signaling of controlinformation could be accomplished in the bearer plane over separatelinks to accomplish a virtual out-of-band signaling means withconcomitant reduction in network security. Furthermore, specific dataprotocols, such as TCP, can be mapped to specific routes, or mapped tospecific ports on the data controllers. This capability allows the datacontrollers to be backward compatible and/or to act as routers. In otherwords, the protocol-to-port mapping extends to data controllers withoutthe need for the data controllers to natively support the protocol.

In general, alternative methods preferably meet all of the followingfour criteria:

1. The network preferably behaves in a connection-oriented manner fortime-sensitive (or other parameter-sensitive) traffic while retainingconnectionless behavior for best-effort traffic.2. The network is preferably controlled with an out-of-band means toenhance security and provide an end-to-end view.3. The network preferably determines and retains current stateinformation with periodic measurements to enable pro-activenear-real-time control.4. The network control logic, although physically distributed, ispreferably logically coherent to enable end-to-end control over one ormultiple networks and to effect significant increases in networkefficiency through better utilization and lower operating costs.

Also, any graphs described herein are not drawn to scale. Theembodiments were chosen and described in order to best explain theprinciples of the invention and its practical applications, to therebyenable others skilled in the art to best utilize the invention andvarious embodiments with various modifications as are suited to theparticular use contemplated. Furthermore, the order of steps in themethod are not necessarily intended to occur in the sequence laid out.It is intended that the scope of the invention be defined by thefollowing claims and their equivalents.

1. A computer-implemented method for end-to-end control of datatransported through an asynchronous network, comprising: receiving areservation request for a data transport session, where said reservationrequest contains a requested class of communication service through theasynchronous network; obtaining at least one end-to-end route throughsaid network, where said route is based on said requested class ofcommunication service and a state of the network; and controlling saiddata transport session, such that data is forced to travel along atleast one route through said asynchronous network.
 2. The method ofclaim 1, wherein said reservation request is received from at least oneserviced device.
 3. The method of claim 1, wherein said controllingfurther comprises controlling multiple data controllers dispersed alongsaid at least one route.
 4. The method of claim 3, wherein saidreceiving further comprises generating said reservation request within amanagement plane.
 5. The method of claim 3, wherein said controllingcomprises mapping specific data protocols to specific routes, or mappingspecific data protocols to specific ports in each data controller. 6.The method of claim 1, where said obtaining comprises selecting at leastone predetermined route through said network from an inventory ofmultiple predetermined routes, where said selecting is at leastpartially based on states of said multiple predetermined routes.
 7. Themethod of claim 1, where said obtaining comprises selecting at least aprimary predetermined route and a backup predetermined route throughsaid network from an inventory of multiple predetermined routes, wheresaid selecting is at least partially based on the states of saidmultiple routes.
 8. The method of claim 1, where said class of serviceis dependent on some weighted combination of the required bandwidth,transport data rate, maximum delay allowed by the class of communicationservice, variations in delay allowed by the class of communicationservice, maximum allowed transport cost, allowed priority relative toother data being transported, or required reliability of said class ofcommunication service.
 9. The method of claim 1, further comprising,before said obtaining, determining the state of the network along saidroute.
 10. The method of claim 9, wherein said determining comprises:instructing a measurement signal to be transported along at least partof said route; and determining whether said measurement signal wastransported and received in accordance with predetermined performancecharacteristic limits.
 11. The method of claim 9, wherein saiddetermining utilizes a common timing reference with sufficient accuracyto enable one-way delay measurements between data controllers dispersedthroughout said network.
 12. The method of claim 9, wherein a timeinterval of said determining is dynamically adjusted based on currentcharacteristics of said route between said data controllers.
 13. Themethod of claim 9, wherein said determining comprises: determiningparametric guard band limits; ascertaining a state of at least part ofsaid network; determining whether said state is outside of said guardband limits; and transmitting an alarm, if said state is outside of saidguard band limits.
 14. The method of claim 9, where said state isdetermined regularly at time intervals sufficiently short to enablenear-real-time control of said network.
 15. The method of claim 9,further comprising transmitting said state of the network to amanagement controller via a out-of-plane dedicated physical circuit oran in-plane dedicated virtual circuit.
 16. The method of claim 1,further comprising, prior to said controlling, receiving data that formspart of said data transport session from a preceding data controlleralong said route or from Customer Premises Equipment (CPE).
 17. Themethod of claim 1, wherein said controlling further comprisestransmitting data that forms part of said data transport session to anext data controller along said route.
 18. The method of claim 1, wheresaid controlling further comprises controlling each of multiple datacontrollers dispersed along said route.
 19. The method of claim 1, wheresaid controlling further comprises changing or sequentially changing adestination address of each data packet in said data transfer session toroute said packet along said route.
 20. The method of claim 1, wheresaid controlling occurs in near-real-time.